Made available in DSpace on 2016-04-28T20:15:29Z (GMT). No. of bitstreams: 1 2008- Daniela de Oliveira Franco Acuna.pdf: 2634530 bytes, checksum: 5433beffd9a4776e67f732e78762b6bb (MD5) Previous issue date: 2008-02-19 / The snail, Achatina fulica (Giant African snail), is registered in almost all Brazilian territory, and may act as an intermediate host of parasites of the man. This study aimed to describe the morphology of the nematode larvae found in A. fulica, through light (LM) and scanning electron microscopy (SEM), and to relate the prevalence of infection to the collection places of the snails and to the antropic activity. Sixty snails were collected from April/2006 to April/2007, in the Mesquita City, RJ, transferred to laboratory, kept in terraria, measured and dissected to verify the infection, distribution of the cysts in tissues of the snails. The cysts were collected and the larvae were separated. The material thus obtained was used to LM and SEM. The occurrence of A. fulica in the less conserved area was greater than that in the more conserved area. However, there was not a significant relation between the intensity of infection and the collection places and the antropic activity. Fourteen snails (23%) were infected and the biggest number of cysts/snail verified was 130 and the minor was 1, in snails that with 106 and 55mm of shell length, respectively. A strong correlation was observed between the size of the snail and the number of cysts and there was a greater concentration of these in the pallial cavity, 87%. Of this total, 49% were in the area more vascularized and 38% in the less vascularized area of this cavity. The cysts presented spherical shape, light pink colored and measured 0.97-1.57mm in diameter and with an unique larva involved by an amorphous material. Two hundred twenty two encysted larvae were recovered, 30 larvae were used to the morphological studies. The length of the larvae varied of 2.57-5.8mm, being classified in: small - until 3.5mm; medium - of 3.53-4.5mm and great - above of 4.52mm. The average length of the larvae in the three groups was of 2.85; 3.87 and 5.23mm, respectively, and the total average of 4.2mm. The larvae presented white cuticle, shining, transversally striated and the lateral line extending to the posterior extremity of the body. In the anterior end, it is observed mouth provided with three lips, with amphids and papillae, followed by a muscular oesophagus with average length of 0.61mm, ending in an esophagus bulb. The nervous ring it was observed in the medium third of the oesophagus and the intestine ends in an opening located next to the posterior end. The tail had a length varying of 0.15-0.42mm, is located after this opening may present two types of endings: abrupt or that it sharpens gradually. The difference in the ending of the tail may suggest sexual dimorphism, although not to have been observed reproductive structures. The identification to the specific level was not possible, this pointed to the necessity of continuation of this study. The expressive population density of A.fulica observed in the conserved area less it confirms the influence of the antropic action on the dispersion of this snail. / O molusco Achatina fulica (Caramujo gigante africano) ? registrado em quase todo territ?rio nacional, havendo a possibilidade de atuar como hospedeiro de parasitos do homem. Este estudo objetivou descrever a morfologia dos est?gios larvais de nemat?ides encontrados em A. fulica, atrav?s de microscopia de luz e eletr?nica de varredura, e relacionar a preval?ncia de infec??o aos locais de coleta dos moluscos e ? atividade antr?pica. Sessenta moluscos foram coletados de abril de 2006 a abril de 2007, no munic?pio de Mesquita, RJ, transferidos para o laborat?rio, mantidos em terr?rios, medidos e dissecados para verifica??o da infec??o, distribui??o dos cistos pelos tecidos do molusco, coleta dos cistos e obten??o das larvas. Procedeu-se a fixa??o e o processamento para microscopia de luz e eletr?nica de varredura. A ocorr?ncia de A. fulica na ?rea menos conservada foi maior que na ?rea mais conservada. Por?m n?o houve uma rela??o significativa entre a intensidade de infec??o aos locais de coleta e ? atividade antr?pica. Quatorze moluscos (23%) estavam infectados e o maior n?mero de cistos verificado por molusco foi de 130 e o menor de 01, em moluscos que apresentavam 106 e 55mm de comprimento de concha, respectivamente. Foi observada uma forte correla??o entre o tamanho do molusco e o n?mero de cistos encontrados e maior concentra??o destes na cavidade paleal, 87%. Desse total, 49% estavam na ?rea mais vascularizada e 38% na menos vascularizada da cavidade. Os cistos apresentavam formato esf?rico, colora??o rosada e mediam de 0,97 a 1,57mm de di?metro e na maioria das vezes com uma ?nica larva que se encontrava envolvida por um material amorfo. Foram recuperadas 222 larvas encistadas. Destas, 30 foram utilizadas no estudo morfol?gico. O comprimento das larvas variou de 2,57 a 5,8mm, sendo classificados em: pequeno at? 3,5mm; m?dio de 3,53 a 4,5mm e grande - acima de 4,52mm. O comprimento m?dio das larvas nos tr?s grupos foi de 2,85; 3,87 e 5,23mm, respectivamente, e a m?dia total de 4,2mm. As larvas apresentavam cut?cula branca, brilhante e estriada no sentido transversal e linha lateral at? a extremidade posterior do corpo. Na extremidade anterior, observa-se a boca provida de tr?s l?bios, com anf?dios e papilas, seguida por um es?fago musculoso com comprimento m?dio de 0,61mm, terminando em um bulbo esofagiano. O anel nervoso foi observado no ter?o m?dio do es?fago e o intestino termina em uma abertura localizada pr?ximo ? extremidade posterior. A cauda, com comprimento variando de 0,15 a 0,42mm, se forma a partir desta abertura e apresenta dois tipos de termina??es: abrupta ou que afina gradativamente. A diferen?a na termina??o da cauda pode sugerir dimorfismo sexual, apesar de n?o terem sido observados prim?rdios de ?rg?os reprodutores. Com os resultados obtidos n?o foi poss?vel a identifica??o ao n?vel espec?fico, havendo dessa forma a necessidade de continua??o deste estudo. A densidade populacional expressiva de A. fulica observada na ?rea menos conservada confirma a influ?ncia da a??o antr?pica sobre a dispers?o deste molusco.